What I did was use old shards of stained glass, some are even old 70's lamps dissasembled and cut up, and I tumble the glass in a rock tumbler sometimes, to get the sharp edges off,(but this can be done by scraping the glass edges together to get the edges dull) and I use clear silicone adhesive to glue the peices to the shower door, leaving a space for grout. then I grout it just like you would tiles on a backsplash or tub surround. I have even bought stained glass off ebay! And also have smashed up glass plates, bottles to use in this fashion.

If a bleach solution doesn't take it off, it may be permanent. It may have been cleaned with abrasives such as comet and the surface ruined. If you think it might be from rust, there are rust removers. Any idea what it is or the type of tub? Gloria

Try a paste of hydrogen peroxide and baking soda and let set 20 minutes. It may take multiple applications. Hydrogen peroxide turns to water after exposure to air about 20 minutes. Wiping tub/shower after each use with squeegie or chamois will tend to keep surfaces dry and minimize mineral deposits and mold/mildew. Leaving shower curtain/door open will improve ventilation into the tub/shower area. Keeping surfaces clean and dry will minimize mold/mildew as will improving bathroom ventilation. Run vent/fan for 30 minutes after bathing to help remove moisture from the air in the bathroom.

Yes, the plumbing needs to be done first. Yes, you may be able to just get another acrylic shower wall to cover over everything, if the wall is not moldy or wet behind the tile that you are looking at. There is no need to replace the tub itself if it is in good shape, even if you do decide to take down the wall tile and replace everything from the studs out. Just make sure the workers cover the tub well to protect it while the work is being done. I am with Monicakm_gw, get some more bids for the work. You might want to have them bid on just replacing the walls with new fiberglass, and on doing the whole new tile job, too. You can see new walls at Lowes, Home Depot, and Menard's online. There is also the whole Marbleite wall option to look into. Local dealers for Marbelite are supposed to be cheaper than buying from big box stores, if I remember right. While you are fixing plumbing, you should probably put in a proper mixing valve to protect from scalds. It is the code now. No one will be able to turn the water too hot to burn themselves and flushing the toilet or using the water elsewhere in the house will not burn the person in the shower anymore, either. I have read the experts here on the forum say that the Symmons Temptrol system is very good and is a good value. Here is one that comes with the shower head and tub spout for under $100. http://www.homedepot.com/p/Symmons-Temptrol-1-Handle-Tub-and-Shower-Faucet-in-Chrome-S-96-2/100643619